Photoactivatable nitrogen-containing bases based on alpha-amino ketones

ABSTRACT

The invention relates to organic compounds having a molecular weight of less than 1000 comprising at least one structural unit of the formula (I)  
                 
 
     (I), in which R 1  is an aromatic or heteroaromatic radical which is capable of absorbing light in the wavelength range from 200 to 650 nm and in doing so brings about cleavage of the adjacent carbon-nitrogen bond.  
     The compounds represent photoinitiators for base-catalysable reactions. Other subjects of the invention are base-polymerizable or crosslinkable compositions comprising compounds having a structural unit of the formula 1, a method of implementing photochemically induced, base-catalysed reactions, and the use of the compounds as photoinitiators for base-catalysed reactions.

[0001] The invention relates to α-amino ketones which can be convertedphotochemically into amidine derivatives, to a process for theirpreparation and to a process for the photochemical preparation of theamidine derivatives. Further subjects of the invention arebase-polymerizable or crosslinkable compositions comprising theseα-amino ketones, a method of implementing photochemically induced,base-catalysed reactions, and the use of the α-amino ketones asphotoinitiators for base-catalysed reactions.

[0002] The photolytic cleavage of specific α-amino ketones into freeradicals and the photopolymerization of olefinically unsaturatedmonomers or oligomers which this initiates have long been known and aredescribed, for example, in U.S. Pat. No. 5,077,402.

[0003] In addition to free-radically polymerizable oligomers ormonomers, base-catalysable systems have been disclosed in particular forphotolithographic processes. These systems require a photoinitiatorwhich on exposure to light releases a base. D. R. MacKean et al., Polym.Mater. Sci. Eng. (1992), 66, 237-238 report, for example, on thephotostructuring of polyimide using specific carbamates asphotoinitiators.

[0004] It has now surprisingly been found that certain α-amino ketoneswhich comprise a structural unit of the formula (I)

[0005] release an amidine group on exposure to visible or UV light. Thisamidine group is sufficiently basic to initiate a large number ofbase-catalysable reactions, especially polymerization reactions. Thecompounds are of high sensitivity and through the choice of thesubstituent R₁ the absorption spectrum can be varied within a widerange.

[0006] The compounds make it possible to prepare so-called one-potsystems with base-catalysable oligomers or monomers having an extremelylong storage life. A polymerization reaction, for example, is initiatedonly after exposure to light. The systems can be formulated with littleor no solvent, since the compounds can be dissolved in the monomers oroligomers without being affected. The active catalyst is formed onlyafter exposure to light. These systems can be employed for numerouspurposes, such as for finishes, coatings, moulding compounds orphotolithographic reproductions.

[0007] The invention provides organic compounds having a molecularweight of less than 1000, comprising at least one structural unit of theformula (I)

[0008] in which R₁ is an aromatic or heteroaromatic radical capable ofabsorbing light in the wavelength range from 200 to 650 nm and in doingso brings about cleavage of the adjacent carbon-nitrogen bond. Thestructural unit of the formula (I) features a divalent and monovalentnitrogen atom and a divalent and monovalent carbon atom, the nitrogenatoms being in β position relative to one another.

[0009] By aromatic or heteroaromatic radicals R₁ are meant those whichconform to the Hückel 4n+2 rule.

[0010] The absorption maximum can be varied within a wide range throughthe choice of the aromatic or heteroaromatic radical R₁, and so thephotosensitivity of the compounds can be shifted from the UV into thedaylight region.

[0011] Preference is given to organic compounds in which the structuralunit of the formula (I) comprises compounds of the formula (II)

[0012] in which

[0013] R₁ is an aromatic or heteroaromatic radical which is capable ofabsorbing light in the wavelength range from 200 to 650 nm and in doingso brings about cleavage of the adjacent carbon-nitrogen bond;

[0014] R₂ and R₃ independently of one another are hydrogen, C₁-C₁₈alkyl,C₃-C₁₈alkenyl, C₃-C₁₈alkynyl or phenyl and, if R₂ is hydrogen orC₁-C₁₈alkyl, R₃ is additionally a group —CO—R₁₄ in which R₁₄ isC₁-C₁₈alkyl or phenyl; or R₁ and R₃, together with the carbonyl groupand the C atom to which R₃ is attached, form a benzocyclopentanoneradical;

[0015] R₅ is C₁-C₁₈alkyl or NR₁₅R₁₆;

[0016] R₄, R₆, R₇, R₁₅ and R₁₆ independently of one another are hydrogenor C₁-C₁₈alkyl; or

[0017] R₄ and R₆ together form a C₂-C₁₂alkylene bridge or

[0018] R₅ and R₇ together, independently of R₄ and R₆, form aC₂-C₁₂alkylene bridge or, if R₅ is NR₁₅R₁₆, R₁₆ and R₇ together form aC₂-C₁₂alkylene bridge.

[0019] Alkyl in the various radicals having up to 18 carbon atoms is abranched or unbranched radical such as methyl, ethyl, propyl, isopropyl,n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl,isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl, 1-methylhexyl,n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl,3-methylheptyl, n-octyl, 2-ethyl-hexyl, 1,1,3-trimethylhexyl,1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl,dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl,hexadecyl, heptadecyl, octadecyl. Preference is given to alkyl having 1to 12, especially 1 to 6 carbon atoms.

[0020] Alkenyl having 3 to 18 carbon atoms is a branched or unbranchedradical such as propenyl, 2-butenyl, 3-butenyl, isobutenyl,n-2,4-pentadienyl, 3-methyl-2-butenyl, n-2-octenyl, n-2-dodecenyl,iso-dodecenyl, oleyl, n-2-octadecenyl or n-4-octadecenyl. Preference isgiven to alkenyl having 3 to 12, especially 3 to 6 carbon atoms.

[0021] Alkynyl having 3 to 18 carbon atoms is a branched or unbranchedradical such as propynyl (—C₂—C≡CH ), 2-butynyl, 3-butynyl, n-2-octynyl,or n-2-octadecynyl. Preference is given to alkynyl having 3 to 12,especially 3 to 6 carbon atoms..

[0022] The C₂-C₁₂alkylene bridge is ethylene, propylene, butylene,pentylene, hexylene, heptylene, octylene, nonylene, decylene, undecyleneor dodecylene.

[0023] R₁ is preferably an aromatic radical which is unsubstituted orsubstituted one or more times by C₁-C₁₈alkyl, C₃-C₁₈alkenyl,C₃-C₁₈alkynyl, C₁-C₁₈haloalkyl, NO₂, NR₈R₉, N₃, OH, CN, OR₁₀, SR₁₀,C(O)R₁₁, C(O)OR₁₂ or halogen and is selected from the group consistingof phenyl, naphthyl, phenanthryl, anthracyl, pyrenyl,5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl,benzo[b]thienyl, naphtho[2,3-b]thienyl, thiathrenyl, dibenzofuryl,chromenyl, xanthenyl, thioxanthyl, phenoxathiinyl, pyrrolyl, imidazolyl,pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl,indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl,phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl,pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl,perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl,isoxazolyl, furazanyl, terphenyl, stilbenyl, fluorenyl or phenoxazinyl,or R₁ is a radical of the formulae A, B or C

[0024] R₈, R₉, R₁₀, R₁₁ and R₁₂ are hydrogen or C₁-C₁₈alkyl;

[0025] R₁₃ is C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl,C₁-C₁₈haloalkyl, NO₂, NR₈R₉, OH, CN, OR₁₀,

[0026] SR₁₀, C(O)R₁₁, C(O)OR₁₂ or halogen; and n is 0 or a number 1, 2or 3.

[0027] Examples of C₁-C₁₈alkyl, C₃-C₁₈alkenyl and C₃-C₁₈alkynyl havealready been indicated above.

[0028] Halogen is fluorine, chlorine, bromine or iodine.

[0029] Examples of C₁-C₁₈haloalkyl are fully or partly halogenatedC₁-C₁₈alkyl. The halogen (halo) here is F, Cl, Br, or I. Examples arethe positional isomers of mono- to decafluoropentyl, mono- tooctafluorobutyl, mono- to hexafluoropropyl, mono- to tetrafluoroethyland mono- and difluoromethyl and also the corresponding chloro, bromoand iodo compounds. Preference is given to the perfluorinated alkylradicals. Examples of these are perfluoropentyl, perfluorobutyl,perfluoropropyl, perfluoroethyl and, in particular, trifluoromethyl.

[0030] Examples of the NR₈R₉ amino group are the respective monoalkyl ordialkylamino groups such as methylamino, ethylamino, propylamino,butylamino, pentylamino, hexylamino, octadecylamino, dimethylamino,diethylamino, dipropylamino, diisopropylamino, di-n-butylamino,di-isobutylamino, dipentylamino, dihexylamino or dioctadecylamino.Further dialkylamino groups are those in which the two radicalsindependently of one another are branched or unbranched, for examplemethylethylamino, methyl-n-propylamino, methylisopropylamino,methyl-n-butylamino, methylisobutylamino, ethylisopropylamino,ethyl-n-butylamino, ethylisobutylamino, ethyl-tert-butylamino,isopropyl-n-butylamino or isopropylisobutylamino.

[0031] The alkoxy group OR₁₀ having up to 18 carbon atoms is a branchedor unbranched radical such as methoxy, ethoxy, propoxy, isopropoxy,n-butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy, octoxy,decyloxy, tetradecyloxy, hexadecyloxy or octadecyloxy. Preference isgiven to alkoxy having 1 to 12, especially 1 to 8, for example 1 to 6carbon atoms.

[0032] Examples of the thioalkyl group SR₁₀ are thiomethyl, thioethyl,thiopropyl, thiobutyl, thiopentyl, thiohexyl, thioheptyl, thiooctyl orthiooctadecyl, it being possible for the alkyl radicals to be linear orbranched.

[0033] Examples of the radical R₁ are phenyl, naphthyl, phenanthryl,anthracyl, pyrenyl, 5,6,7,8-tetrahydro-2-naphthyl,5,6,7,8-tetrahydro-1-naphthyl, thienyl, benzo[b]thienyl,naphtho[2,3-b]thienyl, thiathrenyl, dibenzofuryl, chromenyl, xanthenyl,phenoxathiinyl, pyrrolyl, imidazolyl, pyrazolyl, pyrazinyl, pyrimidinyl,pyridazinyl, indolizinyl, isoindolyl, indolyl, indazolyl, purinyl,quinolizinyl, isoquinolyl, quinolyl, phthalazinyl, naphthyridinyl,quinoxalinyl, quinazolinyl, cinnolinyl, pteridinyl, carbazolyl,β-carbolinyl, phenanthridinyl, acridinyl, perimidinyl, phenanthrolinyl,phenazinyl, isothiazolyl, phenothiazinyl, isoxazolyl, furazanyl,biphenyl, stilbenyl, terphenyl, fluorenyl, phenoxazinyl, methoxyphenyl,2,4-dimethoxyphenyl, 2,4,6-trimethoxyphenyl, bromophenyl, tolyl, xylyl,mesityl, nitrophenyl, dimethylaminophenyl, diethylaminophenyl,aminophenyl, diaminophenyl, 1-naphthyl, 2-naphthyl,1-phenylamino-4-naphthyl, 1-methylnaphthyl, 2-methylnaphthyl,1-methoxy-2-naphthyl, 2-methoxy-1-naphthyl, 1-dimethylamino-2-naphthyl,1,2-dimethyl-4-naphthyl, 1,2-dimethyl-6-naphthyl,1,2-dimethyl-7-naphthyl, 1,3-dimethyl-6-naphthyl,1,4-dimethyl-6-naphthyl, 1,5-dimethyl-2-naphthyl,1,6-dimethyl-2-naphthyl, 1-hydroxy-2-naphthyl, 2-hydroxy-1-naphthyl,1,4-dihydroxy-2-naphthyl, 7-phenanthryl, 1-anthryl, 2-anthryl,9-anthryl, 3-benzo[b]thienyl, 5-benzo[b]thienyl, 2-benzo[b]thienyl,4-dibenzofuryl, 4,7-dibenzofuryl, 4-methyl-7-dibenzo-furyl, 2-xanthenyl,8-methyl-2-xanthenyl, 3-xanthenyl, 2-phenoxathiinyl, 2,7-phenoxathiinyl,2-pyrrolyl, 3-pyrrolyl, 5-methyl-3-pyrrolyl, 2-imidazolyl, 4-imidazolyl,5-imidazolyl, 2-methyl-4-imidazolyl, 2-ethyl-4-imidazolyl,2-ethyl-5-imidazolyl, 3-pyrazolyl, 1-methyl-3-pyrazolyl,1-propyl-4-pyrazolyl, 2-pyrazinyl, 5,6-dimethyl-2-pyrazinyl,2-indolizinyl, 2-methyl-3-isoindolyl, 2-methyl-1-isoindolyl,1-methyl-2-indolyl, 1-methyl-3-indolyl, 1,5-dimethyl-2-indolyl,1-methyl-3-indazolyl, 2,7-dimethyl-8-purinyl,2-methoxy-7-methyl-8-purinyl, 2-quinolizinyl, 3-isoquinolyl,6-isoquinolyl, 7-isoquinolyl, isoquinolyl, 3-methoxy-6-isoquinolyl,2-quinolyl, 6-quinolyl, 7-quinolyl, 2-methoxy-3-quinolyl,2-methoxy-6-quinolyl, 6-phthalazinyl, 7-phthalazinyl,1-methoxy-6-phthalazinyl, 1,4-dimethoxy-6-phthalazinyl,1,8naphthyridin-2-yl, 2-quinoxalinyl, 6-quinoxalinyl,2,3-dimethyl-6-quinoxalinyl, 2,3-dimethoxy-6-quinoxalinyl,2-quinazolinyl, 7-quinazolinyl, 2-dimethylamino-6-quinazolinyl,3-cinnolinyl, 6-cinnolinyl, 7-cinnolinyl, 3-methoxy-7-cinnolinyl,2-pteridinyl, 6-pteridinyl, 7-pteridinyl, 6,7-dimethoxy-2-pteridinyl,2-carbazolyl, 3-carbazolyl, 9-methyl-2-carbazolyl,9-methyl-3-carbazolyl, β-carbolin-3-yl, 1-methyl-β-carbolin-3-yl,1-methyl-β-carbolin-6-yl, 3-phenanthridinyl, 2-acridinyl, 3-acridinyl,2-perimidinyl, 1-methyl-5-perimidinyl, 5-phenanthrolinyl,6-phenanthrolinyl, 1-phenazinyl, 2-phenazinyl, 3-isothiazolyl,4-isothiazolyl, 5-isothiazolyl, 2-phenothiazinyl, 3-phenothiazinyl,10-methyl-3-phenothiazinyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl,4-methyl-3-furazanyl, 2-phenoxazinyl or 10-methyl-2-phenoxazinyl.

[0034] Radicals substituted one or more times are, for example,substituted 1 to 5 times, 1 to 4 times or 3 times, 2 times or once.

[0035] Where R₁ and R₃, together with the carbonyl group and the C atomto which R₃ is attached, form a benzocyclopentanone radical, this meansstructures as follows

[0036] With particular preference R₁ is phenyl, naphthyl, pyrenyl,thioxanthyl or phenothiazinyl each of which is unsubstituted orsubstituted one or more times by C₁-C₁₈alkyl, C₁-C₁₈-haloalkyl, NR₈R₉,CN, NO₂, N₃, SR₁₀ or OR₁₀, or R₁ is a radical of the formulae A, B or C

[0037] in which n is 0 and the radicals R₈, R₉, R₁₀ and R₁₃ are asdefined above.

[0038] Further particularly preferred compounds are those in which R₁ isphenyl, naphthyl, anthracyl, thioxanthyl, dibenzofuranyl or pyrenyl, theradicals phenyl, naphthyl, anthracyl, thioxanthyl and pyrenyl beingunsubstituted or being substituted one or more times by CN, NR₈R₉, NO₂,halogen, N₃, CF₃, SR₁₀ or OR₁₀, or R₁ is a radical of the formulae A, Bor C.

[0039] in which n is 0 and the radicals R₈, R₉, R₁₀ and R₁₃ are asdefined above. With very particular preference R₁ is phenyl,4-aminophenyl, 4-methylthiophenyl, 4-trifluoro-methylphenyl,4-nitrophenyl, 2,4,6-trimethoxyphenyl, 2,4-dimethoxyphenyl, naphthyl,anthracyl or pyrenyl or a radical of the formula A or B

[0040] in which n is 0.

[0041] R₂ and R₃ independently of one another are preferably hydrogen orC₁-C₆alkyl. It is likewise preferred for R₄ and R₆ together to be aC₂-C₆alkylene bridge.

[0042] Preferably, R₅ and R₇ are a C₂-C₆alkylene bridge or, if R₅ isNR₁₅R₁₆, R₁₆ and R₇ together are a C₂-C₆alkylene bridge.

[0043] R₇ is preferably a C₂-C₆alkylene bridge together with R₅ or R₇ isC₁-C₁₈alkyl which is branched in the α-position of the N-atom.

[0044] A particularly preferred group of compounds of the formula (II)are those in which R₁ is phenyl, naphthyl, anthracyl, thioxanthyl,dibenzofuranyl or pyrenyl, the phenyl radical being unsubstituted orbeing substituted one or more times by CN, NR₈R₉, NO₂, N₃, halogen, CF₃,SR₁₀ or OR₁₀, or R₁ is a radical of the formulae A, B or C

[0045] n is 0 and the radicals R₈, R₉, R₁₀ and R₁₃ are hydrogen orC₁-C₁₄alkyl;

[0046] R₂ and R₃ are hydrogen or C₁-C₆alkyl; or R₁ and R₃, together withthe carbonyl group and the C atom to which R₃ is attached, form abenzocyclopentanone radical;

[0047] R₄, R₆ and R₇ independently of one another are hydrogen orC₁-C₆alkyl;

[0048] R₅ is C₁-C₆alkyl or NR₁₅R₁₆, where R₁₅ and R₁₆ are hydrogen orC₁-C₆alkyl; or

[0049] R₄ and R₆ together form a C₂-C₆alkylene bridge; or, independentlyof R₄ and R₆,

[0050] R₅ and R₇ together form a C₂-C₆alkylene bridge or, if R₅ isNR₁₅R₁₆, R₁₆ and R₇ together form a C₂-C₆alkylene bridge.

[0051] The invention additionally provides a process for preparingcompounds having the structural unit of the formula (I), which comprisesreacting a compound comprising a structural unit of the formula (III)

[0052] with a compound comprising a structural unit of the formula (IV)

[0053] in which R₁ is as defined above, including the preferredmeanings, and Halogen is F, Cl, Br or I, preferably Br.

[0054] Preference is given to a process for preparing compounds of theformula (II) which comprises reacting a compound of the formula (V)

[0055] with a compound of the formula (VI)

[0056] in which R₁, R₂, R₃, R₄, R₅, R₆ and R₇ are as defined above,including the preferred meanings, and Halogen is F, Cl, Br or I.

[0057] The reaction can be carried out in a conventional manner. It isadvantageous to use a solvent or solvent mixture, for examplehydrocarbons (benzene, toluene, xylene), halogenated hydrocarbons(methylene chloride, chloroform, carbon tetrachloride, chlorobenzene),alkanols (methanol, ethanol, ethylene glycol monomethyl ether) andethers (diethyl ether, dibutyl ether, ethylene glycol dimethyl ether) ormixtures thereof.

[0058] The reaction can be carried out within a temperature range from−10° C. to +100° C. It is preferably carried out at from 10° C. to 50°C.

[0059] The invention likewise provides a process for preparing acompound of the formula (VII)

[0060] which comprises exposing a compound of the formula (II)

[0061] to light having a wavelength from 200 nm to 650 nm. The reactionis advantageously carried out in a solvent or solvent mixture. Theconcentration of the compounds of the formula (II) is advantageouslyadjusted so that virtually all of the light is absorbed in the reactionvessel.

[0062] The reaction solution is preferably stirred and, if desired,cooled in the course of the exposure.

[0063] Suitable solvents have been listed above.

[0064] The invention additionally provides a composition comprising

[0065] A) at least one compound having a structural unit of the formula(I) and

[0066] B) at least one organic compound capable of a base-catalysedaddition or substitution reaction.

[0067] Preference is given to compositions comprising as component A)organic components in which the structural unit of the formula (I)comprises compounds of the formula (II)

[0068] in which the radicals R₁, R₂, R₃, R₄, R₅, R₆ and R₇ are asdefined above, including their preferred meanings.

[0069] The base-catalysed addition or substitution reaction can becarried out with low molecular mass compounds (monomers), witholigomers, with polymeric compounds or with a mixture of thesecompounds. Examples of reactions which can be carried out both withmonomers and with oligomers/polymers using the novel photoinitiators arethe Knoevenagel reaction or the Michael addition reaction.

[0070] Of particular importance are compositions in which component B)is an anionically polymerizable or crosslinkable organic material.

[0071] The organic material can be in the form of mono- orpolyfunctional monomers, oligomers or polymers.

[0072] Particularly preferred oligomeric/polymeric systems are bindersor coating systems as are customary in the coatings industry.

[0073] Examples of such base-catalysable binders or coating systems are:

[0074] a) Acrylate copolymers having alkoxysilane or alkoxysiloxane sidegroups, for example the polymers described in U.S. Pat. No. 4,772,672 orU.S. Pat. No. 4,444,974;

[0075] b) Two-component systems comprising hydroxyl-containingpolyacrylates, polyesters and/or polyethers and aliphatic or aromaticpolyisocyanates;

[0076] c) Two-component systems comprising functional polyacrylates anda polyepoxide, where the polyacrylate contains carboxyl or anhydridegroups;

[0077] d) Two-component systems comprising fluorine-modified orsilicone-modified hydroxyl-containing polyacrylates, polyesters and/orpolyethers and aliphatic or aromatic polyisocyanates;

[0078] e) Two-component systems comprising (poly)ketimines and aliphaticor aromatic polyisocyanates;

[0079] f) Two-component systems comprising (poly)ketimines andunsaturated acrylate resins or acetoacetate resins or methyla-acrylamidomethylglycolate;

[0080] g) Two-component systems comprising polyamines and polyacrylatescontaining anhydride groups;

[0081] h) Two-component systems comprising (poly)oxazolidines andpolyacrylates containing anhydride groups, or unsaturated acrylateresins or polyisocyanates;

[0082] i) Two-component systems comprising epoxy-containingpolyacrylates and carboxyl-containing polyacrylates;

[0083] l) Polymers based on allyl glycidyl ether;

[0084] m) Two-component systems comprising a (poly)alcohol and a(poly)isocyanate;

[0085] n) Two-component systems comprising an α,β-ethylenicallyunsaturated carbonyl compound and a polymer which contains activated CH₂groups, it being possible for the activated CH₂ groups to be presenteither in the main chain or in the side chain or in both, as isdescribed, for example, in EP-B-0 161 697 for (poly)malonate groups.Other compounds having activated CH₂ groups are (poly)acetoacetates and(poly)cyanoacetates.

[0086] Among these base-catalysable binders particular preference isgiven to the following:

[0087] b) Two-component systems comprising hydroxyl-containingpolyacrylates, polyesters and/or polyethers and aliphatic or aromaticpolyisocyanates;

[0088] c) Two-component systems comprising functional polyacrylates anda polyepoxide, where the polyacrylate contains carboxyl or anhydridegroups;

[0089] i) Two-component systems comprising epoxy-containingpolyacrylates and carboxyl-containing polyacrylates;

[0090] m) two-component systems comprising a (poly)alcohol and a(poly)isocyanate, and

[0091] n) two-component systems comprising an α,β-ethylenicallyunsaturated carbonyl compound and a polymer which contains activated CH₂groups, it being possible for the activated CH₂ groups to be presenteither in the main chain or in the side chain or in both, as isdescribed, for example, in EP-B-0 161 697 for (poly)malonate groups.Other compounds having activated CH₂ groups are (poly)acetoacetates and(poly)cyanoacetates.

[0092] Two-component systems comprising an α,β-ethylenically unsaturatedcarbonyl compound and a (poly)malonate, and their preparation, aredescribed in EP-B-0 161 687. The malonate group here can be attached ina polyurethane, polyester, polyacrylate, epoxy resin, polyamide orpolyvinyl polymer either in the main chain or in a side chain. Theα,β-ethylenically unsaturated carbonyl compound employed can be anydouble bond activated by a carbonyl group. Examples are esters or amidesof acrylic acid or methacrylic acid. In the ester groups it is alsopossible for additional hydroxyl groups to be present. Diesters andtriesters are also possible.

[0093] Typical examples are hexanediol diacrylate or trimethylolpropanetriacrylate. Instead of the acrylic acid it is also possible to useother acids and their esters or amides, such as crotonic or cinnamicacid.

[0094] Under base catalysis, the components of the system react with oneanother at room temperature to form a crosslinked coating system whichis suitable for numerous applications. Owing to its good inherentweathering resistance it is suitable, for example, for exteriorapplications as well and can, if required, be additionally stabilized byUV absorbers and other light stabilizers.

[0095] Other systems suitable as component B) in the novel compositionsare epoxy systems. Epoxy resins are suitable for preparing novel,curable mixtures comprising epoxy resins as component B) are those whichare customary in epoxy resin technology, examples of such epoxy resinsbeing:

[0096] I) Polyglycidyl and poly(β-methylglycidyl) esters, obtainable byreacting a compound, having at least two carboxyl groups in the moleculewith epichlorohydrin or β-methyl-epichlorohydrin. The reaction isjudiciously carried out in the presence of bases. As the compound havingat least two carboxyl groups in the molecule it is possible to usealiphatic polycarboxylic acids. Examples of such polycarboxylic acidsare oxalic, succinic, glutaric, adipic, pimelic, suberic, azelaic ordimerized or trimerized linoleic acid. It is also possible, however, toemploy cycloaliphatic polycarboxylic acids, such as tetrahydrophthalic,4-methyltetrahydrophthalic, hexahydrophthalic or4-methylhexahydrophthalic acid, for example. Aromatic polycarboxylicacids, furthermore, can be used, such as phthalic, isophthalic orterephthalic acid, for example.

[0097] II) Polyglycidyl or poly(β-methylglycidyl) ethers, obtainable byreacting a compound having at least two free alcoholic hydroxyl groupsand/or phenolic hydroxyl groups with epichlorohydrin orβ-methylepichlorohydrin under alkaline conditions or in the presence ofan acidic catalyst with subsequent alkali treatment.

[0098] The glycidyl ethers of this type are derived, for example, fromacyclic alcohols, such as ethylene glycol, diethylene glycol and higherpoly(oxyethylene) glycols, propane-1,2-diol or poly(oxypropylene)glycols, propane-1,3-diol, butane-1,4-diol, poly(oxytetramethylene)glycols, pentane-1,5-diol, hexane-1,6-diol, hexane-2,4,6-triol,glycerol, 1,1,1-trimethylolpropane, pentaerythritol, sorbitol, and frompolyepichlorohydrins. They also derive, however, for example, fromcycloaliphatic alcohols, such as 1,4-cyclohexanedimethanol,bis(4-hydroxycyclohexyl)methane or 2,2-bis(4-hydroxycyclohexyl)propane,or possess aromatic nuclei, such as N,N-bis(2-hydroxyethyl)aniline orp,p′-bis(2-hydroxyethylamino)-diphenylmethane. The glycidyl ethers canalso be derived from mononuclear phenols, such as resorcinol orhydroquinone, for example, or are based on polynuclear phenols, such asbis(4-hydroxyphenyl)methane, 4,4′-dihydroxybiphenyl,bis(4-hydroxyphenyl) sulfone, 1,1,2,2-tetrakis(4-hydroxyphenyl)ethane,2,2-bis(4-hydroxyphenyl)propane,2,2-bis(3,5-dibromo-4-hydroxyphenyl)propane and from novolaks,obtainable by condensing aldehydes, such as formaldehyde, acetaldehyde,chloral or furfuraldehyde, with phenols, such as phenol, or with phenolswhose nucleus is substituted by chlorine atoms or C₁-C₉alkyl groups,examples being 4-chlorophenol, 2-methylphenol, or 4-tert-butylphenol, orby condensation with bisphenols, those of the type specified above.

[0099] III) Poly(N-glycidyl) compounds, obtainable bydehydrochlorination of the reaction products of epichlorohydrin withamines containing at least two amine hydrogen atoms. These amines are,for example, aniline, n-butylamine, bis(4-aminophenyl)methane,m-xylylenediamine or bis(4-methylaminophenyl)methane. Thepoly(N-glycidyl) compounds also, however, include triglycidylisocyanurate, N,N′-diglycidyl derivatives of cycloalkyleneureas, such asethyleneurea or 1,3-propyleneurea, and diglycidyl derivatives ofhydantoins, such as of 5,5-dimethylhydantoin.

[0100] IV) Poly(S-glycidyl) compounds, for example di-S-glycidylderivatives derived from dithiols such as ethane-1,2-dithiol orbis(4-mercaptomethylphenyl) ether.

[0101] V) Cycloaliphatic epoxy resins, for examplebis(2,3-epoxycyclopentyl) ether, 2,3-epoxy-cyclopentyl glycidyl ether,1,2-bis(2,3-epoxycyclopentyloxy)ethane or 3,4-epoxycyclohexymethyl3′,4′-epoxycyclohexanecarboxylate.

[0102] Alternatively it is possible to use epoxy resins in which the1,2-epoxide groups are attached to different heteroatoms and/orfunctional groups; these compounds include, for example, theN,N,O-triglycidyl derivative of 4-aminophenol, the glycidyl etherglycidyl ester of salicylic acid,N-glycidyl-N′-(2-glycidyloxypropyl)-5,5-dimethylhydantoin or2-glycidyloxy-1,3-bis(5,5-dim ethyl-1-glycidylhydantoin-3-yl)propane.

[0103] Mixtures of epoxy resins can also be used as component B).

[0104] The compositions comprise the photoinitiator, component A),preferably in an amount of from 0.01 to 10% by weight, based on thecomponent B).

[0105] In addition to the photoinitiator, component A), thephotopolymerizable mixtures may include various additives. Examples ofthese are thermal inhibitors which are intended to prevent prematurepolymerization, such as hydroquinone, hydroquinone derivatives,p-methoxyphenol, β-naphthol or sterically hindered phenols such as2,6-di(tert-butyl)-p-cresol, for example. To increase the dark storagestability it is possible, for example, to use copper compounds, such ascopper naphthenate, stearate or octoate, phosphorus compounds, such astriphenylphosphine, tributylphosphine, triethyl phosphite, triphenylphosphite or tribenzyl phosphite, quaternary ammonium compounds, such astetramethylammonium chloride or trimethylbenzylammonium chloride, orhydroxylamine derivatives, such as N-diethyl-hydroxylamine. To excludeatmospheric oxygen during polymerization it is possible to add paraffinor similar waxlike substances, which owing to their lack of solubilityin the polymer migrate to the surface at the beginning of polymerizationwhere they form a transparent surface layer which prevents the ingressof air. It is likewise possible to apply an oxygen-impermeable layer.Light stabilizers which can be added, in a small amount, are UVabsorbers such as those, for example, of the hydroxyphenylbenzotriazole,hydroxyphenyl-benzophenone, oxalamide or hydroxyphenyl-s-triazine type.Individual compounds or mixtures of these compounds can be used, with orwithout the deployment of sterically hindered amines (HALS).

[0106] Examples of such UV absorbers and light stabilizers are givenbelow.

[0107] 1.2-(2′-Hydroxyphenyl)benzotriazoles, for example2-(2′-hydroxy-5′-methylphenyl)-benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(5′-tert-butyl-2′-hydroxyphenyl)benzotriazole,2-(2′-hydroxy-5′-(1,1,3,3-tetramethylbutyl)phenyl)-benzotriazole,2-(3′,5′-di-tert-butyl-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-methylphenyl)-5-chlorobenzotriazole,2-(3′-sec-butyl-5′-tert-butyl-2′-hydroxy phenyl)benzotriazole,2-(2′-hydroxy-4′-octoxyphenyl)benzotriazole,2-(3′,5′-di-tert-amyl-2′-hydroxyphenyl)benzotriazole,2-(3′,5′-bis(α,α-dimethylbenzyl)-2′-hydroxyphenyl)benzotriazole, mixtureof2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-methoxycarbonylethyl)phenyl)-benzotriazole,2-(3′-tert-butyl-2′-hydroxy-5′-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3′-tert-butyl-5′-[2-(2-ethylhexyloxy)carbonylethyl]-2′-hydroxyphenyl)benzotriazole,2-(3′-dodecyl-2′-hydroxy-5′-methylphenyl)benzotriazole and2-(3′-tert-butyl-2′-hydroxy5′-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2′-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol];transesterification product of2-[3′-tert-butyl-5′-(2-methoxycarbonylethyl)-2′-hydroxyphenyl]benzotriazolewith polyethylene glycol 300; [R—CH₂CH₂—COO(CH₂)₃]₂— whereR=3′-tert-butyl-4′-hydroxy-5′-2H-benzotriazol-2-ylphenyl.

[0108] 2.2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy-,4-octoxy-, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2′,4′-trihydroxy and2′-hydroxy-4,4′-dimethoxy derivative.

[0109] 3. Esters of substituted and unsubstituted benzoic acids, forexample 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butyl-benzoyl)resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate and 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

[0110] 4. Acrylates, for example ethyl or isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methyl andbutyl α-cyano-β-methyl-p-methoxycinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methyl-indoline.

[0111] 5. Sterically hindered amines, such asbis(2,2,6,6-tetramethylpiperidyl) sebacate,bis(2,2,6,6-tetramethylpiperidyl) succinate,bis(1,2,2,6,6-pentamethylpiperidyl) sebacate, bis(1,2,2,6,6-pentamethylpiperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, condensation productof 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidine and succinicacid, condensation product ofN,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetraoate,1,1′-(1,2-ethanediyl)-bis(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro-[4.5]decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, condensationproduct of N,N′-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamineand 4-morpholino-2,6-dichloro-1,3,5-triazine, condensation product of2-chloro-4,6-di-(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, condensation product of2-chloro-4,6-di-(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro[4.5]decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione.

[0112] 6. Oxalamides, for example 4,4′-dioctyloxyoxanilide,2,2′-diethoxyoxanilide, 2,2′-dioctyloxy-5,5′-di-tert-butyloxanilide,2,2′-di-dodecyloxy-5,5′-di-tert-butyloxanilide,2-ethoxy-2′-ethyloxanilide, N,N′-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2′-ethyloxanilide and its mixture with2-ethoxy-2′-ethyl-5,4′-di-tert-butyloxanilide, mixtures of o- andp-methoxy- and of o- and p-ethoxy-disubstituted oxanilides.

[0113] 7.2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[2-hydroxy-4-(2-hydroxy-3-butyloxypropyloxy)-phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropyloxy)phenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-[4-dodecyl/tridecyloxy-(2-hydroxypropyl)oxy-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

[0114] 8. Phosphites and phosphonites, for example, triphenyl phosphite,diphenyl alkyl phosphites, phenyl dialkyl phosphites, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,diisodecyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis-isodecyloxy pentaerythritoldiphosphite, bis(2,4-di-tert-butyl-6-methylphenyl) pentaerythritoldiphosphite, bis(2,4,6-tri-tert-butylphenyl) pentaerythritoldiphosphite, tristearyl sorbitol triphosphite,tetrakis(2,4-di-tert-butylphenyl)-4,4′-biphenylenediphosphonite,6-isooctyloxy-2,4,8,10-tetra-tert-butyl-12H-dibenzo[d,g]-1,3,2-dioxaphosphocin,6-fluoro-2,4,8,10-tetra-tert-butyl-12-methyldibenzo[d,g]-1,3,2-dioxaphosphocin,bis-(2,4-di-tert-butyl-6-methylphenyl) methyl phosphite,bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite.

[0115] Examples of further additives are:

[0116] Fillers and reinforcing agents, for example calcium carbonate,silicates, glass fibres, glass beads, asbestos, talc, kaolin, mica,barium sulfate, metal oxides and hydroxides, carbon black, graphite,wood flour and flours or fibres of other natural products, syntheticfibres.

[0117] Other additives, for example plasticizers, lubricants,emulsifiers, pigments, rheological additives, catalysts, levellingassistants, optical brighteners, flameproofing agents, antistatics,blowing agents.

[0118] In addition to the additives indicated above it is also possiblefor additional coinitiators to be present. In general these are dyeswhich improve the overall quantum yield by means, for example, of energytransfer or electron transfer. Examples of suitable dyes which can beadded as coinitiators are triarylmethanes, for example malachite green,indolines, thiazines, for example methylene blue, xanthones,thioxanthones, oxazines, acridines or phenazines, for example safranine,and rhodamines of the formula

[0119] in which R is alkyl or aryl and R¹ is hydrogen, an alkyl or arylradical, for example Rhodamine B, Rhodamine 6G or Violamine R, and alsoSulforhodamine B or Sulforhodamine G.

[0120] Preference is given to thioxanthones, oxazines, acridines,phenazines and rhodamines.

[0121] In addition to the above-described base-catalysable (curable)binders, component B), the composition may also include other binders aswell. Further olefinically unsaturated compounds, for example, arepossible. The unsaturated compounds may include one or more olefinicallydouble bonds. They may be of low molecular mass (monomeric) or highermolecular mass (oligomeric). Examples of monomers having a double bondare alkyl or hydroxyalkyl acrylates or methacrylates, such as methyl,ethyl, butyl, 2-ethylhexyl or 2-hydroxyethyl acrylate, isbornylacrylate, methyl methacrylate or ethyl methacrylate. Silicone acrylatesare also of interest. Further examples are acrylonitrile, acrylamide,methacrylamide, N-substituted (meth)acrylamides, vinyl esters such asvinyl acetate, vinyl ethers such as isobutyl vinyl ether, styrene,alkyl- and halostyrenes, N-vinylpyrrolidone, vinyl chloride orvinylidene chloride.

[0122] Examples of monomers having two or more double bonds are thediacrylates of ethylene glycol, propylene glycol, neopentyl glycol,hexamethylene glycol or bisphenol A,4,4′-bis(2-acryloyloxyethoxy)diphenylpropane, trimethylolpropanetriacrylate, pentaerythritol triacrylate or tetraacrylate, vinylacrylate, divinyl benzene, divinyl succinate, diallyl phthalate,triallyl phosphate, triallyl isocyanurate ortris(2-acryloylethyl)isocyanurate.

[0123] Examples of polyunsaturated compounds of relatively highmolecular mass (oligomers) are acrylicized epoxy resins, acrylicizedpolyesters or polyesters containing vinyl ether groups or epoxy groups,polyurethanes and polyethers. Further examples of unsaturated oligomersare unsaturated polyester resins which are mostly prepared from maleicacid, phthalic acid and one or more diols and have molecular weights offrom about 500 to 3000. In addition it is also possible to employ vinylether monomers and oligomers, and also maleate-terminated oligomers withpolyester, polyurethane, polyether, polyvinyl ether and epoxy mainchains. In particular, combinations of vinyl ether-functional oligomersand polymers as are described in WO 90/01512 are very suitable. Alsosuitable, however, are copolymers of vinyl ether and maleicacid-functionalized monomers. Unsaturated oligomers of this kind canalso be referred to as prepolymers.

[0124] Particularly suitable examples are esters of ethylenicallyunsaturated carboxylic acids and polyols or polyepoxides, and polymershaving ethylenically unsaturated groups in the chain or in side groups,such as unsaturated polyesters, polyamides and polyurethanes andcopolymers thereof, alkyd resins, polybutadiene and butadienecopolymers, polyisoprene and isoprene copolymers, polymers andcopolymers having (meth)acrylic groups in side chains, and mixtures ofone or more such polymers.

[0125] If, in addition, use is made of such free-radically curablemonomers, oligomers/polymers then it is judicious to add a furtherphotoinitiator which dissociates into free radicals. Suchphotoinitiators are known and are produced industrially. Examples arebenzophenone, benzophenone derivatives, acetophenone, acetophenonederivatives, for example α-hydroxycycloalkyl phenyl ketones,dialkoxyacetophenones, α-hydroxy- or α-aminoacetophenones,4-aroyl-1,3-dioxolanes, benzoin alkyl ethers and benzil ketals, monoacylphosphine oxides, bisacylphosphine oxides, ferrocenium compounds ortitanocenes.

[0126] Examples are specified in U.S. Pat. No. 5077402. Polymer systemsof this kind, in which curing/crosslinking takes place by differentmechanisms, are also referred to as hybrid systems.

[0127] The novel compositions can also have added to them non-reactivebinders, which is particularly judicious if the photopolymerizablecompounds are liquid or viscous substances. The amount of thenon-reactive binder can be, for example, 5-95%, preferably 10-90% and,in particular, 40-90% by weight, based on the overall solids content.The choice of non-reactive binder is made in accordance with the fieldof use and with the properties required for this use, such as thepossibility for development in aqueous and organic solvent systems,adhesion to substrates, and sensitivity to oxygen.

[0128] Examples of suitable binders are polymers having a molecularweight of around 5000-2,000,000, preferably 10,000-1,000,000. Examplesare: homo- and copolymeric acrylates and methacrylates, for examplecopolymers of methyl methacrylate/ethyl acrylate/methacrylic acid,poly(alkyl methacrylates), poly(alkyl acrylates); cellulose esters andethers, such as cellulose acetate, cellulose acetate butyrate,methylcellulose, ethylcellulose; polyvinylbutyral, polyvinylformal,cyclized rubber, polyethers such as polyethylene oxide, polypropyleneoxide, polytetrahydrofuran; polystyrene, polycarbonate, polyurethane,chlorinated polyolefins, polyvinyl chloride, copolymers of vinylchloride/vinylidene chloride, copolymers of vinylidene chloride withacrylonitrile, methyl methacrylate and vinyl acetate, polyvinyl acetate,copoly(ethylene/vinyl acetate), polymers such as polycaprolactam andpoly(hexamethylene adipamide) and polyesters such as poly(ethyleneglycol terephtalate) and poly(hexamethylene glycol succinate).

[0129] The invention additionally provides a method of implementingbase-catalysed reactions which comprises subjecting

[0130] A) at least one compound comprising a structural unit of theformula (I)

[0131] in which R₁ is an aromatic or heteroaromatic radical which iscapable of absorbing light in the wavelength range from 200 to 650 nmand in doing so brings about cleavage of the adjacent carbon-nitrogenbond; and

[0132] B) at least one organic compound which is capable of abase-catalysed reaction to irradiation with light having a wavelength offrom 200 nm to 650 nm.

[0133] Component A) is preferably an organic compound in which thestructural unit of the formula (I) comprises compounds of the formula(II)

[0134] in which R₁, R₂, R₃, R₄, R₅, R₆ and R₇ are as defined above,including their preferred meanings.

[0135] Examples and preferred meanings for base-catalysed reactions havealready been given above.

[0136] With particular preference, component B) is an anionicallypolymerizable or crosslinkable organic material..

[0137] In some cases it may be advantageous to carry out heating duringor after exposure to light. In this way it is possible in many cases toaccelerate the crosslinking reaction.

[0138] The sensitivity of the novel compositions to light generallyextends from about 200 nm through the UV region and into the infraredregion (about 20,000 nm, in particular 1200 nm) and therefore spans avery broad range. Suitable radiation comprises, for example, sunlight orlight from artificial light sources. Therefore, a large number of verydifferent types of light source can be used. Both point sources and flatradiators (lamp carpets) are suitable. Examples are carbon arc lamps,xenon arc lamps, medium-pressure, high-pressure and low-pressure mercurylamps, doped if desired with metal halides (metal halogen lamps),microwave-stimulated metal vapour lamps, excimer lamps, superactinicfluorescent tubes, fluorescent lamps, incandescent argon lamps,electronic flashlights, photographic flood lamps, electron beams andX-rays, produced by means of synchrotrons or laser plasma. The distancebetween the lamp and the substrate according to the invention which isto be exposed can vary depending on the application and on the typeand/or power of the lamp, for example between 2 cm and 150 cm. Alsoespecially suitable are laser light sources, for example excimer lasers.Lasers in the visible region or in the IR region can also be employed.Very advantageous here is the high sensitivity of the novel materialsand the possibility of adapting a dye as coinitiator to the laser line.By this method it is possible to produce printed circuits in theelectronics industry, lithographic offset printing plates or reliefprinting plates, and also photographic image recording materials.

[0139] The novel compositions can be employed for various purposes, forexample as printing inks, as clearcoats, as white paints, for examplefor wood or metal, as coating materials, inter alia for paper, wood,metal or plastic, as powder coatings, as daylight-curable coatings formarking buildings and roads, for photographic reproduction processes,for holographic recording materials, for image recording processes orfor the production of printing plates which can be developed usingorganic solvents or aqueous-alkaline media, for the production of masksfor screen printing, as dental filling materials, as adhesives,including pressure-sensitive adhesives, as laminating resins, as etchresists or permanent resists and as solder masks for electroniccircuits, for the production of three-dimensional articles by masscuring (UV curing in transparent moulds) or by the stereolithographyprocess, as is described, for example, in U.S. Pat. No. 4,575,330, forthe preparation of composite materials (for example styrenic polyesters,which may contain glass fibres and/or other fibres and other assistants)and other thick-layer compositions, for the coating or encapsulation ofelectronic components, or as coatings for optical fibres.

[0140] In surface coatings, it is common to use mixtures of a prepolymerwith polyunsaturated monomers which also contain a monounsaturatedmonomer. The prepolymer here is primarily responsible for the propertiesof the coating film, and varying it allows the skilled worker toinfluence the properties of the cured film. The polyunsaturated monomerfunctions as a crosslinker, which renders the coating film insoluble.The monounsaturated monomer functions as a reactive diluent, by means ofwhich the viscosity is reduced without the need to use a solvent.

[0141] Unsaturated polyester resins are mostly used in two-componentsystems in conjunction with a monounsaturated monomer, preferablystyrene. For photoresists, specific one-component systems are frequentlyemployed, for example polymaleinimides, polychalcones or polyimides, asdescribed in DE-A-2 308 830.

[0142] The novel photocurable compositions are suitable, for example, ascoating materials for substrates of all kinds, examples being wood,textiles, paper, ceramic, glass, plastics such as polyesters,polyethylene terephthalate, polyolefins or cellulose acetate, especiallyin the form of films, and also metals such as Al, Cu, Ni, Fe, Zn, Mg orCo and GaAs, Si or SiO₂, on which it is the intention to apply aprotective coating or, by imagewise exposure, an image.

[0143] The substrates can be coated by applying a liquid composition, asolution or suspension to the substrate. The choice of solvent and theconcentration depend predominantly on the type of composition and thecoating process. The solvent should be inert: in other words, it shouldnot undergo any chemical reaction with the components and should becapable of being removed again after the coating operation, in thedrying process. Examples of suitable solvents are ketones, ethers andesters, such as methyl ethyl ketone, isobutyl methyl ketone,cyclopentanone, cyclohexanone, N-methylpyrrolidone, dioxane,tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol,1-methoxy-2-propanol, 1,2-dimethoxyethane, ethyl acetate, n-butylacetate and ethyl 3-ethoxypropionate.

[0144] Using known coating processes, the solution is applied uniformlyto a substrate, for example by spin coating, dip coating, knife coating,curtain coating, brushing, spraying—especially electrostaticspraying—and reverse roll coating and by electrophoretic deposition. Itis also possible to apply the photosensitive layer to a temporary,flexible support and then to coat the final substrate, for example acopper-clad circuit board, by means of layer transfer via lamination.

[0145] The amount applied (layer thickness) and the nature of thesubstrate (layer support) are functions of the desired field ofapplication. The range of layer thicknesses generally comprises valuesfrom about 0.1 μm to more than 100 μm.

[0146] The novel radiation-sensitive compositions can also be subjectedto imagewise exposure. In this case they are used as negative resists.They are suitable for electronics (galvanoresists, etch resists andsolder resists), for the production of printing plates, such as offsetprinting plates, flexographic and relief printing plates or screenprinting plates, for the production of marking stamps, and can be usedfor chemical milling or as micro resists in the production of integratedcircuits. There is a correspondingly wide range of variation in thepossible layer supports and in the processing conditions of the coatedsubstrates.

[0147] The term “imagewise” exposure relates both to exposure through aphotomask containing a predetermined pattern, for example a slide,exposure by a laser beam which is moved under computer control, forexample, over the surface of the coated substrate and so generates animage, and irradiation with computer-controlled electron beams.

[0148] Following the imagewise exposure of the material and prior todeveloping, it may be advantageous to carry out a brief thermaltreatment, in which only the exposed parts are thermally cured. Thetemperatures employed are generally 50-150° C. and preferably 80-130°C.; the duration of the thermal treatment is generally between 0.25 and10 minutes.

[0149] A further field of use for photocuring is that of metal coating,for example the surface-coating of metal panels and tubes, cans orbottle tops, and photocuring on polymer coatings, for example of flooror wall coverings based on PVC.

[0150] Examples of the photocuring of paper coatings are the colourlessvarnishing of labels, record sleeves or book covers.

[0151] The use of the novel compounds for curing shaped articles madefrom composite compositions is likewise of interest. The compositecomposition is made up of a self-supporting matrix material, for examplea glass-fibre fabric, or else, for example, of plant fibres [cf. K. -P.Mieck, T. Reussmann in Kunststoffe 85 (1995), 366-370], which isimpregnated with the photocuring formulation. Shaped articles which areproduced from composite compositions using the compounds according tothe invention are of high mechanical stability and resistance. Thecompounds of the invention can also be used as photocuring agents inmoulding, impregnating and coating compositions, as are described, forexample, in EP-A-7086. Examples of such compositions are fine coatingresins on which stringent requirements are placed with respect to theircuring activity and resistance to yellowing, or fibre-reinforcedmouldings such as planar or longitudinally or transversely corrugatedlight diffusing panels.

[0152] The invention additionally provides for the use of an organiccompound comprising at least one structural unit of the formula (I)

[0153] in which R₁ is an aromatic or heteroaromatic radical which iscapable of absorbing light in the wavelength range from 200 to 650 nmand on doing so brings about cleavage of the adjacent carbon-nitrogenbond, as a photoinitiator for photochemically induced, base-catalysedaddition or substitution reactions.

[0154] Preference is given to an organic compound in which thestructural unit of the formula (I) comprises compounds of the formula(II)

[0155] in which the radicals R₁, R₂, R₃, R₄, R₅, R₆ and R₇ are asdefined above, including their preferred meanings.

[0156] Examples and preferences for base-catalysed addition orsubstitution reactions have been given above.

[0157] The invention provides, furthermore, a coated substrate which hasbeen coated on at least one surface with a composition as describedabove, and a process for the photographic production of relief images,in which a coated substrate is subjected to imagewise exposure and thenthe unexposed areas are removed with a solvent. Of particular interestin this context is the abovementioned exposure by means of a laser beam.

[0158] The examples which follow illustrate the invention. As in theremainder of the description and in the claims, parts and percentagesare by weight unless stated otherwise. If alkyl or alkoxy radicalshaving more than three C atoms are indicated without reference to theirisomeric form, then the respective n-isomers are meant.

A-EXAMPLES Preparing the Photoinitiators Example A1

[0159]

[0160] [R₁=phenyl, R₂=R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0161] A solution of a-bromoacetophenone in toluene is added withstirring to a solution of 1,5-diazabicyclo[4.3.0]nonane in toluene. Themixture is stirred overnight at room temperature. The reaction mixtureis filtered, washed with demineralized water and dried over MgSO₄. It issubsequently dried further in vacuo to give yields of about 85%.

[0162] U.V. (CHCl₃) max. at 246 nm (ε 10400 l/mol cm).

[0163]¹H-NMR (CDCl₃) [ppm]: 8.04 (2H, d, ArH), 7.48 (1H, t, ArH), 7.34(2H, t, ArH), 4.04 (1H, d, NCH₂CO), 3.46 (1H, d, NCH₂CO), 3.02 (2H, m,NCH₂), 2.87 (1H, m, NCH), 2.59 (1H, m, NCH) and 2.3-1.3 (9H, m, CH₂).

[0164]¹³C-NMR (CDCl₃) [ppm]: 197.98, 136.16, 133.14, 128.73, 128.50,84.04, 61.04, 53.08, 52.14, 51.18, 29.10, 24.24 and 19.37.

[0165] The examples below are prepared similarly to Example A1. Thecorresponding product is obtained in all cases with a yield of about85%.

Example A2

[0166] [R₁=diphenyl, R₂=R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0167] U.V. (CHCl₃) max. at 287 nm (ε 19600 l/mol cm).

[0168]¹H-NMR (CDCl₃) [ppm]: 8.18 (2H, d, ArH), 7.65-7.15 (7H, m, ArH),4.05 (1H, d, NCH₂CO), 3.50 (1H, d, NCH₂CO), 3.09 (2H, m, NCH₂), 2.61(1H, m, NCH) and 2.3-1.4 (9H, m, CH₂).

[0169]¹³C-NMR (CDCl₃) [ppm]: 197.68,145.82, 140.05,134.84,129.40,128.98, 128.22,127.32, 127.18, 84.16, 61.30, 53.14, 52.17,51.20, 29.14, 24.29 and 19.38.

Example A3

[0170] [R₁=naphthyl, R₂=R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0171] Elemental analysis calculated for C₁₈H₂₂N₂O: C, 76.56;H, 7.85; N,9.92; found: C, 76.83; H, 7.52; N, 9.42,

[0172] U.V. (CHCl₃) max. at 251 nm (ε 39100 l/mol cm), 286 nm (ε 8200l/mol cm) and 345 nm (ε 1700 l/mol cm).

[0173]¹H-NMR (CDCl₃) [ppm]: 8.62 (1H, s, ArH), 8.09 (1H, dd, ArH), 7.94(1H, d, ArH), 7.83 (2H, m, ArH), 7.54 (2H, m, ArH), 4.15 (1H, d,NCH₂CO), 3.65 (1H, d, NCH₂CO), 3.07 (3H, m, NCH₂), 2.70 (1H, m, NCH) and2.4-1.4 (9H, m, CH₂).

[0174]¹³C-NMR (CDCl₃) [ppm]: 197.92, 135.69, 132.52, 130.38, 129.80,128.47, 128.31, 127.77, 126.65, 124.38, 84.02, 60.74, 53.14, 52.10,51.22, 29.09, 24.06 and 19.46.

Example A4

[0175] [R₁=pyrene, R₂=R₃=H, R₄/R₆=—(CH₂)₃—, R_(5/)R₇=—(CH₂)₃—]

[0176] Elemental analysis calculated for C₂₅H₂₄N₂O: C, 81.49;H, 6.57;found: C, 81.70;H, 6.74.

[0177] U.V. (CHCl₃) max. at 245 nm (ε 29800 l/mol cm), 285 nm (ε 20900l/mol cm) and 360 nm (ε 18100 l/mol cm).

[0178]¹H-NMR (CDCl₃) [ppm]: 8.84 (1H, d, ArH), 8.44 (1H, d, ArH),8.24-7.93 (7H, m, ArH), 4.18 (1H, d, NCH₂CO), 3.66 (1H, d, NCH₂CO), 3.01(3H, m, NCH₂), 2.64 (1H, t, NCH) and 2.4-1.3 (9H, m, CH₂).

[0179]¹³C-NMR (CDCl₃) [ppm]: 202.83, 133.90, 131.09, 130.56, 129.9,129.55, 129.08, 128.27, 127.20, 126.37, 126.30, 126.03, 125.05, 124.70,124.04, 83.86, 63.26, 53.23, 52.05, 51.12, 29.13, 24.19 and 19.42.

Example A5

[0180] [R₁=4-azidophenyl, R₂=R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0181]¹H-NMR (CDCl₃) [ppm]: 8.10 (2H, d, ArH), 6.99 (2H, d, ArH), 3.93(1H, d, NCH₂CO), 3.35 (1H, d, NCH₂CO), 3.02 (2H, m, NCH₂), 2.84 (1H, m,NCH), 2.49 (1H, m, NCH) and 2.3-1.3 (9H, m, CH₂). TABLE 1 ExamplesA6-A36;

Example R₁ R₂ R₃ R₅/R₇ R₄/R₆ A6  Phenyl H H —(CH₂)₅— —(CH₂)₃— A7  PhenylH H —(CH₂)₃—NH— —(CH₂)₃— A8  Naphthyl H H —(CH₂)₅— —(CH₂)₃— A9  NaphthylH H —(CH₂)₃—NH— —(CH₂)₃— A10 4-Aminophenyl H H —(CH₂)₃— —(CH₂)₃— A114-Aminophenyl H H —(CH₂)₃—NH— —(CH₂)₃— A12 4-Aminophenyl H H —(CH₂)₅——(CH₂)₃— A-13 4-Cyanophenyl H H —(CH₂)₃— —(CH₂)₃— A-14 4-Cyanophenyl H H—(CH₂)₃—NH— —(CH₂)₃— A15 4-Cyanophenyl H H —(CH₂)₅— (CH₂)₃— A164-Nitrophenyl H H —(CH₂)₃— —(CH₂)₃— A17 4-Nitrophenyl H H —(CH₂)₃—NH——(CH₂)₃— A18 4-Nitrophenyl H H —(CH₂)₅— —(CH₂)₃— A194-Trifluoromethylphenyl H H —(CH₂)₃— —(CH₂)₃— A204-Trifluoromethylphenyl H H —(CH₂)₃—NH— —(CH₂)₃— A214-Trifluoromethylphenyl H H —(CH₂)₅— —(CH₂)₃— A22 4-DimethylaminophenylH H —(CH₂)₃— —(CH₂)₃— A23 4-Dimethylaminophenyl H H —(CH₂)₃—NH— —(CH₂)₃—A24 4-Dimethylaminophenyl H H —(CH₂)₅— —(CH₂)₃— A252,4,6-Trimethoxyphenyl H H —(CH₂)₃— —(CH₂)₃— A26 2,4,6-TrimethoxyphenylH H —(CH₂)₃—NH— —(CH₂)₃— A27 2,4,6-Trimethoxyphenyl H H —(CH₂)₅——(CH₂)₃— A28 4-(C₁₄H₂₉—O)phenyl H H —(CH₂)₃— —(CH₂)₃— A294-(C₁₄H₂₉—O)phenyl H H —(CH₂)₃—NH— —(CH₂)₃— A30 4-(C₁₄H₂₉—O)phenyl H H—(CH₂)₅— —(CH₂)₃— A31

H H —(CH₂)₃— —(CH₂)₃— A32

H H —(CH₂)₃—NH— —(CH₂)₃— A33

H H —(CH₂)₅— —(CH₂)₃— A34

H H —(CH₂)₃— —(CH₂)₃— A35

H H —(CH₂)₃—NH— —(CH₂)₃— A36

H H —(CH₂)₅— —(CH₂)₃—

[0182] TABLE 2 Examples A37-A39;

Exam- ple R₂ R₁/R₃ R₄/R₆ R₅/R₇ A37 H

—(CH₂)₃—NH— —(CH₂)₃— A38 H

—(CH₂)₅— —(CH₂)₃— A39 H

—(CH₂)₃— —(CH₂)₃—

[0183] TABLE 3 Examples A40-A59;

Example R₁ R₂ R₃ R₄ R₅ R₆ R₇ A40 Phenyl H H H NH₂ H H A41 Phenyl H H HNH(C₂H₅) C₂H₅ H A42 Phenyl H H H N(CH₃)₂ H H A43 Phenyl H H H N(CH₃)₂ HCH₃ A44 Phenyl H H H N(CH₃)₂ H H A45 Phenyl H H CH₃ N(CH₃)₂ CH₃ CH₃ A46Phenyl H H H N(CH₃)₂ CH₃ CH₃ A47 Phenyl H H CH₃ N(CH₃)₂ H CH₃ A48 PhenylH H H N(CH₃)₂ H CH₃ A49 Phenyl H H CH₃ N(CH₃)₂ H CH₃ A50 Naphthyl H H HNH₂ H H A51 Naphthyl H H H NH(C₂H₅) C₂H₅ H A52 Naphthyl H H H N(CH₃)₂ HH A53 Naphthyl H H H N(CH₃)₂ H CH₃ A54 Naphthyl H H H N(CH₃)₂ H H A55Naphthyl H H CH₃ N(CH₃)₂ CH₃ CH₃ A56 Naphthyl H H H N(CH₃)₂ CH₃ CH₃ A57Naphthyl H H CH₃ N(CH₃)₂ H CH₃ A58 Naphthyl H H H N(CH₃)₂ H CH₃ A59Naphthyl H H CH₃ N(CH₃)₂ H CH₃

Example A60

[0184] [R₁=

[0185] ; R₂R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

Example A61

[0186] [R₁=4-Diethylaminophenyl, R₂=R₃=H, R₄/R₆=—(CH₂)₃—,R₅/R₇=—(CH₂)₃—]

[0187] Yellow solid (yield 87%);

[0188] Elemental analysis calculated for C₁₉H₂₉N₃O: C 72.34, H 9.27, N13.32; found: C 72.06, H 9.16, N 13.20.

[0189] U.V. (CHCl₃) max. at 247 nm (ε 4700), 313 nm (ε 17300) and 364 nm(ε 5800).

[0190] I.R. (KBr) 1684 cm⁻¹ (C═O).

[0191]¹H NMR (CDCl₃) [ppm]: 7.99 (2H, d, ArH), 6.52 (2H, d, ArH), 3.92(1H, d, NCH₂CO), 3.34 (4H, q, CH₂CH₃), 3.31 (1H, d, NCH₂CO), 3.02 (2H,m, NCH₂), 2.89 (1H, m, NCH), 2.52 (1H, m, NCH), 2.2-1.3 (9H, m, CH₂) and1.10 (6H, t, CH₂CH₃).

[0192]¹³C-NMR (CDCl₃) [ppm]: 195.61, 151.21, 131.40, 123.59, 110.06,84.25, 61.07, 52.87, 52.21, 51.23, 44.55, 29.10, 24.46, 19.41 and 12.58.

Example A62

[0193]

[0194] Red rubberlike solid (yield 72%)

[0195] U.V. (CHCl₃) max. at 245 nm (ε 6700) and 330 nm (ε 23100).

[0196]¹H-NMR (CDCl₃) [ppm]: 8.20 (2H, d, ArH), 7.89-7.43 (7H, m, ArH),4.03 (1H, d, NCH₂CO), 3.49 (1H, d, NCH₂CO), 3.05 (2H, m, NCH₂), 2.91(1H, m, NCH), 2.60 (1H, m, NCH) and 2.3-1.4 (8H, m, CH₂).

Example A63

[0197]

[0198] Orange-colored oil (yield 78%)

[0199] U.V. (CHCl₃) max. at 287 nm (ε 20500).

[0200] I.R. (KBr) 1690 cm⁻¹ (C═O).

[0201]¹³C-NMR (CDCl₃) [ppm]: 1989.14, 145.64, 139.79, 134.85, 128.97,128.82, 128.22, 127.29, 127.16, 125.33, 82.15, 56.34, 55.51, 53.57,52.10, 32.90, 29.07, 24.42, 24.61 and 21.48.

Example A64

[0202] [R₁=phenyl, R₂=CH₃, R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0203] Orange-coloured oil (yield 86%)

[0204] I.R. (KBr) 1695 cm⁻¹ (C═O).

[0205]¹H-NMR (CDCl₃) [ppm]: 8.17 (2H, d, J=7.0 Hz, ArH), 7.50-7.35 (3H,m, ArH), 4.50/1H, q, J=6.6 Hz, NHCHCH₃), 3.05 (2H, m, NCH₂), 2.69 (2H,m, NCH₂), 2.49 (1H, m, NCH), 2.3-1.3 (8H, m, CH₃) and 1.16 (3H, d, J=6.6Hz, CH₃).

[0206]¹³C-NMR (CDCl₃) [ppm]: 200.72, 136.61, 132.65, 129.31, 128.37,81.83, 60.09, 52.31, 51.40, 45.50, 28.76, 25.01, 19.21 and 6.55.

Example A65

[0207]

[0208] Orange-coloured oil (yield 89%).

[0209] U.V. (CHCl₃) max. at 268 nm (ε 10100) and 302 (ε 7300)

[0210] I.R. (KBr) 1670 and 1600 cm⁻¹ (C═O).

[0211]¹H-NMR (CDCl₃) [ppm]: 7.75 (2H, d, ArH), 6.48 (2H, d, ArH), 6.40(1H, s, ArH), 3.96 (1H, d, NCH₂CO), 3.85 (3H, s, OCH₃), 3.80 (3H, s,OCH₃), 3.65 (1H, d, NCH₂CO), 3.03 (3H, m, NCH₂), 2.77 (1H, m, NCH), 2.35(1H, m, NCH) and 2.2-1.3 (8H, m, CH₂).

[0212]¹³C-NMR (CDCl₃) [ppm]: 198.70, 164.35, 160.51, 132.66, 105.24,98.28, 83.23, 63.65, 55.54, 55.45, 52.89, 52.04, 51.33, 28.85, 24.39 and19.44.

Example A66

[0213]

[0214] Orange crystals (yield 94%).

[0215] U.V. (CHCl₃) max. at 244 nm (ε 5400) and 306 (ε 17300)

[0216] I.R. (KBr) 1670 and 1590 cm⁻¹ (C═O).

[0217]¹H-NMR (CDCl₃) [ppm]: 7.96 (2H, d, J=8.8 Hz, ArH), 7.14 (2H, d,J=8.8 Hz, ArH), 3.91 (1H, d, J=15.0 Hz, NCH₂CO), 3.34 (1H, d, J=15.0 Hz,NCH₂CO), 3.00 (2H, m, NCH₂), 2.84 (1H, m, NCH), 2.49 (1H, m, NCH), 2.47(3H, s, SCH₃) and 2.2-1.3 (9H, m, CH₂).

[0218]¹³C-NMR (CDCl₃) [ppm]: 196.99, 145.90, 132.39, 129.22, 129.03,128.23, 125.30, 124.86, 84.12, 61.28, 53.05, 52.12, 51.11, 29.10, 24.28,19.34 and 14.75.

Example A67

[0219]

[0220] U.V. (CHCl₃) max. at 245 nm (ε 44800), 345 nm (ε 3400), 370 nm (ε3800) and 395 nm (ε 3700).

[0221] I.R. (KBr) 1670 cm⁻¹ (C═O).

[0222]¹H-NMR (CDCl₃) [ppm]: 8.85 (1H, s, ArH), 8.54 (1H, s, ArH), 8.49(1H, s, ArH), 8.45 (1H, s, ArH), 8.12 (1H, dd, ArH), 7.99 (2H, m, ArH),7.66-7.46 (2H, m, ArH), 4.18 (1H, d, J=15.2 Hz, NCH₂CO), 3.64 (1H, d,J=15.2 Hz, NCH₂CO), 3.08 (3H, m, NCH₂), 2.70 (1H, m, NCH), and 2.4-1.4(9H, m, CH₂).

Example A68

[0223]

[0224] U.V. (CHCl₃) max. at 258 nm (ε 14100).

[0225] I.R. (KBr) 1685 and 1585 cm⁻¹ (C═O).

[0226]¹H-NMR (CDCl₃) [ppm]: 8.00 (2H, d, J₁=4.1 Hz, J₂=2.3 Hz, ArH),7.98 (2H, dd, J₁=4.1 Hz, J₂=2.3 Hz, ArH), 3.95 (1H, d, J=15.0 Hz,NCH₂CO), 3.40 (1H, d, J=15.0 Hz, NCH₂CO), 3.06 (2H, m, NCH₂), 2.87 (1H,m, NCH), 2.55 (1H, m, NCH) and 2.2-1.3 (9H, m, CH₂).

[0227]¹³C-NMR (CDCl₃) [ppm]: 197.12, 134.77, 131.80, 130.45, 129.06,128.35, 125.32, 84.18, 61.54, 53.17, 52.13, 51.09, 29.14, 24.26 and19.32.

Example A69

[0228]

[0229]¹H-NMR (CDCl₃) [ppm]: 8.27 (2H, d, J=8.8 Hz, ArH), 8.09 (2H, d,J=8.8 Hz, ArH), 3.92 (1H, d, J=15.1 Hz, NCH₂CO), 3.31 (1H, d, J=15.1 Hz,NCH₂CO), 3.07 (2H, m, NCH₂), 2.89 (1H, m, NCH), 2.55 (1H, m, NCH) and2.2-1.3 (9H, m, CH₂). TABLE 4 Example A70-A82;

Example R₁ R₂ R₃ R₅/R₇ R₄/R₆ A70 Phenyl H CH₃ —(CH₂)₅— —(CH₂)₃— A71Phenyl H CH₃ —(CH₂)₃— —(CH₂)₃— A72 Phenyl H Phenyl —(CH₂)₅— —(CH₂)₃— A73Phenyl H Phenyl —(CH₂)₃— —(CH₂)₃— A74 Phenyl CH₃ CH₃ —(CH₂)₅— —(CH₂)₃—A75 Phenyl CH₃ CH₃ —(CH₂)₃— —(CH₂)₃—  A76* 2-Thioxanthyl H H —(CH₂)₅——(CH₂)₃— A77 2-Thioxantyl H H —(CH₂)₃— —(CH₂)₃— A78 2-Thioxanthyl CH₃CH₃ —(CH₂)₅— —(CH₂)₃— A79 2-Thioxanthyl CH₃ CH₃ —(CH₂)₃— —(CH₂)₃— A802-Thioxanthyl H CH₃ —(CH₂)₅— —(CH₂)₃— A81 2-Thioxanthyl H CH₃ —(CH₂)₃——(CH₂)₃— A82 2-Thioxanthyl H H —(CH₂)₃— —(CH₂)₃—

[0230] The compound of Example 76 is obtained as follows: abase-catalysed coupling reaction of thiosalicylic acid andp-bromacetophenone in the presence of copper is used to obtain the ketoacid which, following dehydrogenation with polyphosphoric acid, givesthe 2-acetylthioxanthone, which is brominated in the α position.Finally, the reaction of the ketone with 1,5-diazabicyclo[4.3.0]nonanegives the compound A76.

Example A83

[0231] [R₁=2-naphthyl, R₂=CH₃, R₃=H, R₄/R₆=—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0232]¹H NMR (CDCl₃) [ppm]: 8.85 (0.65H, s), 8.68 (0.35H, s), 8.44-7.44(6H, m, ArH), 4.63 (0.65H, q, J 6.5 Hz, NCHCH₃), 4.61 (0.35H, q, J 6.9Hz, NCHCH₃), 3.14-2.53 (4H, m), 2.28-1.38 (9H, m), 1.39 (1.05H, d, J 6.9Hz, CH₃) and 1.22 (1.95H, d, J 6.5 Hz, CH₃).

Example A84

[0233] [R₁=diphenyl, R₂=CH₃, R₃=H, R₄/R₆—(CH₂)₃—, R₅/R₇=—(CH₂)₃—]

[0234]¹H NMR (CDCl₃): 8.25 (1.5H, m, ArH), 8.01 (0.5H, m, ArH), 7.60(3H, m, ArH), 7.40 (4H, m, ArH), 4.53 (0.75H, q, J 6.6 Hz, NCHCH₃), 4.45(0.25H, q, J 7.0 Hz, NCHCH₃), 3.08 (2H, m), 2.73-1.46 (11H, m), 1.36(0.75H, d, J 7.0 Hz, CH₃), 1.19 (2.25H, d, J 6.5 Hz, CH₃).

B-EXAMPLES Use: Base Catalysis with Monomeric Compounds Examples B1-B4UV-Initiated Michael Addition.

[0235] 7.4×10⁻⁵ mol of photoinitiator (latent amidine base) aredissolved in a mixture of dimethyl malonate and n-butyl acrylate (1:1,200 mg corresponding to 7.4×10⁻⁴ mol) in a quartz vessel. The mixture isirradiated with a high-pressure mercury lamp (200 W) from a distance of30 cm. The conversion is monitored as a function of time.

[0236] The results are set out in Table 5. TABLE 5 Crosslinking [%]after exposure for Example Initiator 0 min 10 min 20 min 30 min 40 minB1 A4 0 26 60  83  91 B2 A1 0 34 74  90 100 B3 A2 0 36 75  92 100 B4 A30 59 91 100

Example B5 Michael Addition Initiated with Visible Light

[0237] 7.4×10⁻⁵ mol of photoinitiator A2 (latent amidine base) and7.4×10⁻⁵ mol of isopropylthioxanthone are dissolved in a mixture ofdimethyl malonate and n-butyl acrylate (1:1,200 mg corresponding to7.4×10⁻⁴ mol) in a glass vessel. The mixture is irradiated with ahalogen lamp (500 watts) from a distance of 30 cm. The conversion ismonitored as a function of time.

[0238] The following result is obtained: Exposure time in minutes 0 30120 300 Conversion in % 0 18 53 88

Examples B6-B9

[0239] The procedure followed is analogous to the method described inExamples B1-B4. The initiators used and the test results are reproducedin Table 6. TABLE 6 Crosslinking [%] after exposure for ExampleInitiator 0 min 10 min 20 min 30 min 40 min B6 A66 0 23 60 83 100 B7 A610 18 49 79  88 B8 A65 0 10 38 70  81 B9 A68 0  8 31 56  72

C-EXAMPLES Use: Base Catalysis with Oligomeric/Polymeric CompoundsExamples C1-C6

[0240] Preparation of a urethane acrylate based on isophoronediisocyanate and 4-hydroxybutyl acrylate.

[0241] The reaction is carried out under a nitrogen atmosphere and allcommercial chemicals used are employed without further purification.

[0242] 1566.8 g (13.78 mol of NCO) of isophorone diisocyanate, 2.3 g ofdibutyltin dilaurate, 2.3 g of 2,5-di-t-butyl-p-cresol and 802.8 g ofbutyl acetate are charged to a three-necked flask with condenser anddropping device. Dry nitrogen is bubbled through the reaction mixtureand the temperature is slowly raised to 60° C. 1987 g (13.78 mol) of4-hydroxybutyl acrylate are added, during which the reaction solutionwarms slowly to 80° C. The temperature is held at 80° C. and thedropping device is flushed with butyl acetate (86.6 g). The reaction ismonitored by titration of the remaining amount of isocyanate, and isover when the isocyanate content is below 0.2% based on the solidscontent. The reaction product obtained has the following physicalproperties:

[0243] Residual 4-hydroxybutyl acrylate: <0.002% based on solids (HPLCanalysis),

[0244] Colour: <<Gardner 1,

[0245] Viscosity: 43 cPa s (20° C.),

[0246] Solids content: 79,3% (1 hour at 140° C.),

[0247] GPC data (polystyrene standard): M_(n) 778, M_(w) 796, d=1.02.

[0248] Preparation of a malonate polyester

[0249] The reaction is carried out under a nitrogen atmosphere and allcommercial chemicals used are employed without further purification.

[0250] In a reaction vessel with stirrer and condenser 1045 g of1,5-pentanediol, 1377.4 g of diethyl malonate and 242.1 g of xylene arecarefully refluxed. The maximum temperature of the reaction mixture is196° C. while the temperature at the head of the condenser is held at79° C. In this way 862 g of ethanol, corresponding to a conversion of97.7%, are distilled off. Then xylene is stripped off in vacuo at atemperature of 200° C. The resulting polymer has a solids content of98.6%, a viscosity of 2710 mPa s and an acid number of 0.3 mg of KOH/gbased on the solids content. M_(n) is 1838, M_(w) is 3186, the colour is175 on the APHA (American Public Health Association) scale (Hazen colournumber; ISO 6271).

Example C1 Curing with UV Light

[0251] 20.5 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example A2 aredissolved in 400 mg of a 1.3:1 mixture of the above-described urethaneacrylate and the malonate polyester. The mixture is exposed to light ina quartz vessel using a high-pressure mercury lamp (200 W) at a distanceof 30 cm. The polymer is tack-free after 45 minutes.

Example C2 Curing with UV Light

[0252] 18.8 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example A3 aredissolved in 400 mg of a 1.3:1 mixture of the above-described urethaneacrylate and the malonate polyester. A film 50 μm thick is drawn outonto a glass plate and is exposed using a high-pressure mercury lamp(200 W) at a distance of 30 cm. The polymer film is tack-free after 30minutes.

Example C3 Curing with Visible Light

[0253] 20.5 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example A2 and10 mg of isopropyl-9H-thioxanthone (6.4×10⁻⁵ mol) are dissolved in 400mg of a 1.3:1 mixture of the above-described urethane acrylate and themalonate polyester. The mixture is exposed to light in a quartz vesselusing a halogen lamp (500 W) at a distance of 30 cm. The polymer istack-free after 120 minutes.

Example C4 Curing with Visible Light

[0254] 20.5 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example A2 and10 mg of isopropyl-9H-thioxanthone (6.4×10⁻⁵ mol) are dissolved in 400mg of a 1.3:1 mixture of the above-described urethane acrylate and themalonate polyester. A film 50 μm thick is drawn out onto a glass plateand is exposed using a halogen lamp (500 W) at a distance of 30 cm. Thepolymer film is tack-free after 120 minutes.

Example C5 Curing with Visible Light

[0255] 18.8 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example A3 and10 mg of isopropyl-9H-thioxanthone (6.4×10⁻⁵ mol) are dissolved in 400mg of a 1.3:1 mixture of the above-described urethane acrylate and themalonate polyester. A film 50 μm thick is drawn out onto a glass plateand is exposed using a halogen lamp (500 W) at a distance of 30 cm. Thepolymer film is tack-free after 120 minutes.

Example C6 Curing with Visible Light

[0256] 18.8 mg (6.4×10⁻⁵ mol) of the photoinitiator from Example Al and10 mg of isopropyl-9H-thioxanthone (6.4×10⁻⁵ mol) are dissolved in 400mg of a 1.3:1 mixture of the above-described urethane acrylate and themalonate polyester. A film 50 μm thick is drawn out onto a glass plateand is exposed using a halogen lamp (500 W) at a distance of 30 cm. Thepolymer film is tack-free after 120 minutes.

Examples C7-C8

[0257] The amounts of photoinitiator from Example A3 andisopropyl-9H-thioxanthone (ITX) stated in Table 6 are dissolved in 400mg of a 1.3:1 mixture of the above-described urethane acrylate and themalonate polyester. A film 50 μm thick is drawn out onto a glass plateand is exposed using a TL03/40 W lamp at a distance of 30 cm. After 4, 6and 24 hours the König pendulum hardness (DIN 53157) and the YellownessIndex in accordance with ASTMD 1925-88 are determined in each case. Theresults are reproduced in Table 7. TABLE 7 Pendulum hardness ExampleInitiator 4 h 6 h 24 h C7 25.0 parts of A3 48 71 154 12.5 parts of ITXC8 25.0 parts of A3 52 92 130  5.0 parts of ITX

What is claimed is:
 1. An organic compound having a molecular weight ofless than 1000 comprising at least one structural unit of the formula(I)

(I), in which R₁ is an aromatic or heteroaromatic radical capable ofabsorbing light in the wavelength range from 200 to 650 nm and in sodoing brings about cleavage of the adjacent carbon-nitrogen bond.
 2. Anorganic compound according to claim 1, wherein the structural unit ofthe formula (I) comprises compounds of the formula (II)

(II), in which R₁ is an aromatic or heteroaromatic radical which iscapable of absorbing light in the wavelength range from 200 to 650 nmand in doing so brings about cleavage of the adjacent carbon-nitrogenbond; R₂ and R₃ independently of one another are hydrogen, C₁-C₁₈alkyl,C₃-C₁₈alkenyl, C₃-C₁₈alkynyl or phenyl and, if R₂ is hydrogen orC₁-C₁₈alkyl, R₃ is additionally a group —CO—R₁₄ in which R₁₄ isC₁-C₁₈alkyl or phenyl; or R₁ and R₃, together with the carbonyl groupand the C atom to which R₃ is attached, form a benzocyclopentanoneradical; R₅ is C₁-C₁₈alkyl or NR₁₅R₁₆; R₄, R₆, R₇, R,₅ and R₁₆independently of one another are hydrogen or C₁-C₁₈alkyl; or R₄ and R₆together form a C₂-C₁₂alkylene bridge or R₅ and R₇ together,independently of R₄ and R₆, form a C₂-C₁₂alkylene bridge or, if R₅ isNR₁₅R₁₆, R₁₆ and R₇ together form a C₂-C₁₂alkylene bridge.
 3. An organiccompound according to claim 1, wherein R₁ is an aromatic radical whichis unsubstituted or substituted one or more times by C₁-C₁₈alkyl,C₃-C₁₈alkenyl, C₃-C₁₈alkynyl, C₁-C₁₈haloalkyl, NO₂, NR₈R₉, N₃, OH, CN,OR₁₀, SR₁₀, C(O)R₁₁, C(O)OR₁₂ or halogen which is selected from thegroup consisting of phenyl, naphthyl, phenanthryl, anthracyl, pyrenyl,5,6,7,8-tetrahydro-2-naphthyl, 5,6,7,8-tetrahydro-1-naphthyl, thienyl,benzo[b]thienyl, naphtho[2,3-b]thienyl, thiathrenyl, dibenzofuryl,chromenyl, xanthenyl, thioxanthyl, phenoxathiinyl, pyrrolyl, imidazolyl,pyrazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, indolizinyl, isoindolyl,indolyl, indazolyl, purinyl, quinolizinyl, isoquinolyl, quinolyl,phthalazinyl, naphthyridinyl, quinoxalinyl, quinazolinyl, cinnolinyl,pteridinyl, carbazolyl, β-carbolinyl, phenanthridinyl, acridinyl,perimidinyl, phenanthrolinyl, phenazinyl, isothiazolyl, phenothiazinyl,isoxazolyl, furazanyl, terphenyl, stilbenyl, fluorenyl or phenoxazinyl,or R₁ is a radical of the formulae A, B or C

R₁₃ is C₁-C₁₈alkyl, C₂-C₁₈alkenyl, C₂-C₁₈alkynyl, C₁-C₁₈haloalkyl, NO₂,NR₈R₉, OH, CN, OR₁₀, SR₁₀, C(O)R₁₁, C(O)OR₁₂ or halogen; R₈, R₉, R₁₀,R₁₁ and R₁₂ are hydrogen or C₁-C₁₈alkyl; and n is 0 or a number 1, 2 or3.
 4. An organic compound according to claim 1, wherein R₁ is phenyl,naphthyl, anthracyl, thioxanthyl, dibenzofuryl or pyrenyl, the radicalsphenyl, naphthyl, anthracyl, thioxanthyl and pyrenyl being unsubstitutedor being substituted one or more times by CN, N₃, NR₈R₉, halogen, NO₂,CF₃, SR₁₀ or OR₁₀, or R₁ is a radical of the formulae A, B or C

in which n is 0 and the radicals R₈, R₉, R₁₀ and R₁₃ are as defined inclaim
 3. 5. An organic compound according to claim 2, wherein R₂ and R₃independently of one another are hydrogen, C₁-C₆alkyl or phenyl.
 6. Acompound according to claim 2, wherein R₄ and R₆ together form aC₂-C₆alkylene bridge.
 7. A compound according to claim 2, wherein R₄ andR₇ form a C₂-C₆alkylene bridge or, if R₅ is NR₁₅R₁₆, R₁₆ and R₇ togetherform a C₂-C₆alkylene bridge.
 8. A compound of the formula (II) accordingto claim 2, wherein R₁ is phenyl, naphthyl, anthracyl, thioxanthyl,dibenzofuranyl or pyrenyl, the phenyl radical being unsubstituted orbeing substituted one or more times by CN, NR₈R₉, N₃, NO₂, CF₃, halogen,SR₁₀ or OR₁₀, or R₁ is a radical of the formulae A, B or C

n is 0 and the radicals R₈, R₉, R₁₀ and R₁₃ are hydrogen or C₁-C₁₄alkyl;R₂ and R₃ are hydrogen or C₁-C₆alkyl or phenyl; or R₁ and R₃, togetherwith the carbonyl group and the C atom to which R₃ is attached, form abenzocyclopentanone radical; R₄, R₆ and R₇ independently of one anotherare hydrogen or C₁-C₆alkyl; R₅ is C₁-C₆alkyl or NR₁₅R₁₆, where R₁₅ andR₁₆ are hydrogen or C₁-C₆alkyl; or R₄ and R₆ together form aC₂-C₆alkylene bridge; or, independently of R₄ and R₆, R₅ and R₇ togetherform a C₂-C₆alkylene bridge or, if R₅ is NR₁₅R₁₅, R₁₆ and R₇ togetherform a C₂-C₆alkylene bridge.
 9. A process for preparing a compoundhaving the structural unit of the formula I according to claim 1, whichcomprises reacting a compound comprising a structural unit of theformula III

with a compound comprising a structural unit of the formula IV

in which R₁ is as defined in claim 1 and Halogen is F, Cl, Br or I. 10.A process for preparing a compound of the formula II according to claim2, which comprises reacting a compound of the formula V

with a compound of the formula VI

in which R₁, R₂, R₃, R₄, R₅, R₆ and R₇ are as defined in claim 2 andHalogen is F, Cl, Br or I.
 11. A process for preparing a compound of theformula VII,

which comprises exposing a compound of the formula II according to claim2 to light having a wavelength from 200 nm to 650 nm.
 12. A compositioncomprising A) at least one compound having a structural unit of theformula II according to claim 1 and B) at least one organic compoundcapable of a base-catalysed addition or substitution reaction.
 13. Acomposition according to claim 12, wherein component B) is ananionically polymerizable or crosslinkable organic material.
 14. Acomposition according to claim 12, wherein component B) is one of thefollowing systems: b) a two-component system comprisinghydroxyl-containing polyacrylates, polyesters and/or polyethers andaliphatic or aromatic polyisocyanates; c) a two-component systemcomprising functional polyacrylates and a polyepoxide, where thepolyacrylate contains carboxyl or anhydride groups; i) a two-componentsystem comprising epoxy-containing polyacrylates and carboxyl-containing polyacrylates; m) a two-component system comprising a(poly)alcohol and a (poly)isocyanate, n) a two-component systemcomprising an α,β-ethylenically unsaturated carbonyl compound and acompound having activated CH₂ groups.
 15. A composition according toclaim 12, wherein component B) is an epoxy system.
 16. A compositionaccording to claim 12, wherein component A) is present in an amount offrom 0.01 to 10% by weight based on component B).
 17. A compositionaccording to claim 12, which additionally comprises a sensitizerselected from the group consisting of thioxanthones, oxazines,acridines, phenazines and rhodamines.
 18. A method of implementingbase-catalysed reactions, which comprises subjecting A) at least onecompound comprising a structural unit of the formula (I)

(I) according to claim 1, in which R₁ is an aromatic or heteroaromaticradical which is capable of absorbing light in the wavelength range from200 to 650 nm and in doing so brings about cleavage of the adjacentcarbon-nitrogen bond; and B) at least one organic compound which iscapable of a base-catalysed reaction to irradiation with light having awavelength of from 200 nm to 650 nm.
 19. A method according to claim 18,wherein heating is carried out during or after exposure to light.
 20. Acoated substrate which has been coated on at least one surface with acomposition according to claim
 12. 21. A polymerized or crosslinkedcomposition according to claim 13.